The present invention relates to an apparatus for monitoring a warp yarn, in particular a leno warp yarn. The invention relates further to weaving machines having an apparatus in accordance with the invention.
One or more leno selvedges can be produced at the edges of a fabric with warp yarns via a leno weave in order to provide a strengthened edge to the fabric. These warp yarns, which are also termed leno warp yarns, are customarily guided and monitored separately from the other warp yarns. It is known to monitor breakage of a warp yarn with a warp stop motion by detecting whether a warp yarn is present or not.
In certain weaving processes or weaving machines, such as, for example, in multiphase weaving machines with a weaving rotor, the problem arises that a warp yarn or a leno warp yarn can be caught by the rotating weaving rotor and wound onto the weaving rotor without breaking the warp yarn or the leno warp yarn. Known warp stop motions are not able to detect such faults.